1. Field of the Invention
The present invention relates to a head drum assembly, and more particularly to a head drum assembly mounting structure on a deck of a tape recorder.
2. Description of the Background Art
Generally, a tape recorder such as a camcorder, VCR, or the like has a fast rotating head drum assembly mounted on a main base of a deck. The head drum assembly includes a magnetic head which scans a traveling magnetic tape for information recording/reproducing.
As shown in FIG. 1, a conventional head drum assembly 20 includes an upper drum 21 and a lower drum 22. The upper drum 21 and lower drum 22 are disposed on a same shaft 23 in such a manner that the upper drum 21 is rotatably supported by the shaft 23, and the lower drum 22 is fixed to the lower portion of the upper drum 21. The head drum assembly 20, constructed as above, usually employs a Helical scanning type in which the head drum assembly 20 is slanted on a predetermined slant with respect to the main base 10 of the deck to stably guide the running of the magnetic tape.
The Helical scanning type head drum assembly 20 includes a guide groove 22a formed on an outer circumference of a lower end of the lower drum 22. Ends of a plurality of brackets 24 are inserted into the guide groove 22a in such a manner as to be spaced from each other by a uniform distance. In this situation, the lower drum 22 and the other ends of the brackets 24 are mounted on the drum base 11 of the main base 10. The other ends of the brackets 24 are fastened to the drum base 11 by screws (S). A reference numeral 22b refers to a lead line, which is an outer circumference of the lower drum 22 stepped to guide the traveling of the magnetic tape. Also, reference numeral 25 is a drum boss received in a central opening of the drum base 11, and S1 refers to coupling holes formed in the brackets 24.
As shown in FIG. 2, the drum base 11 is a ring type rib, for example, having an opening formed in the center thereof, three screw coupling holes S2 formed therein at a uniform distance from each other, and a pair of positioning pins 11a and 11b. 
FIG. 3 is a sectional view taken on line III—III of FIG. 2. The drum base 11 is usually integrally formed with the main base 10 by proper processes such as a drawing, or the like, on a predetermined slant with respect to the main base 10.
The pair of positioning pins 11a and 11b stand substantially in a perpendicular relation with the slant plane of the drum base 11. The positioning pins 11a and 11b determine the mounting position and posture of the lower drum 22 which is mounted on the drum base 11, by a complementary connection with a positioning hole (not shown) formed in a lower surface of the drum boss 25. Accordingly, screw coupling holes (S1 and S2) of the drum base 11 and the brackets 24 are aligned with each other, permitting the screw (S) to pass therethrough and fasten.
In the conventional head drum assembly mounting structure, however, due to the fact that the brackets 24 press the lead line 22b while the drum base 11 and the brackets 24 are fastened by the screws (S), the lead line 22b of the lower drum 22 is often deformed.
Further, in order to insert one end of each of the brackets 24 into the lower drum 22, many processes are required, such as a process of processing the guide groove 22a for receiving the ends of the brackets 24, and also many parts are required, such as three brackets 24, the screw (S) and the pair of positioning pins 11a and 11b, or the like. Accordingly, due to deteriorated assembly efficiency and increased manufacturing cost, productivity is deteriorated.